The present invention relates to an inspecting apparatus which senses an inspection work by a camera and automatically inspects the inspection work and, more particularly, to an inspection status display method of displaying the inspection status of an inspection work.
PGA (Pin Grid Array) has conventionally been known as a packaging technique which meets demands for a larger number of IC or LSI pins. In PGA, a ceramic board is used as a package base for mounting a chip, and wires are laid out to lead line extraction positions. The manufacture of this ceramic board uses a green sheet prepared by kneading alumina power with a liquid binder and shaping the resultant material into a sheet. A past containing a refractory metal is screen-printed on the green sheet. A necessary number of sheets are stacked and baked, performing so-called simultaneous baking of baking the green sheet and metalizing the paste.
A pattern on such a green sheet is inspected by the human eye using a microscope after pattern formation. Visual inspection of a fine pattern requires a skill and overuses the eye. From this, there is proposed a pattern inspecting apparatus which sense a pattern formed on a green sheet or the like by a TV camera and automatically checks the pattern.
FIGS. 5 and 6 explain a conventional inspecting method of detecting disconnection. A master pattern formed by sensing a pattern to be measured that is determined as a nondefective is registered as a set of straight lines representing pattern edges. The pattern to be measured is input as a set of edge data (edge coordinates) representing pattern edges extracted from a gray-scale image obtained by sensing a pattern. Extracted edge data n1, n2, n3, . . . of the pattern to be measured and the straight lines of the master data are made to correspond to each other. For this correspondence, bisectors A2′, A3′, . . . which bisect angles defined by consecutive straight lines A1 and A2, A2 and A3, . . . of the master pattern are obtained, as shown in FIG. 5.
The bisectors A2′, A3′, . . . divide the peripheries of the straight lines A1, A2, A3, . . . into regions belonging to the respective straight lines. The edge data n1, n2, n3, . . . of the pattern to be measured that exist in respective regions are made to correspond to the straight lines A1, A2, A3, . . . of the master pattern to which the respective regions belong. For example, in FIG. 5, the edge data n1 to n3 are made to correspond to the straight line A1, whereas the edge data n4 to n6 are made to correspond to the straight line A2.
After that, the edge data of the pattern to be measured and the master pattern are compared to inspect whether the pattern to be measured is disconnected.
This inspection is realized by labeling processing of tracking the coupled edge data n1 to n9 of the pattern to be measured and thus tracking the pattern edge. At this time, edge data are not coupled at a disconnected portion owing to disconnection at the end of the pattern to be measured. Edge data corresponding to the straight lines A3 to A5 of the master pattern do not exist. As a result, disconnection of the pattern to be measured can be detected.
FIG. 7 explains a conventional inspecting method of detecting a short circuit. Coupled edge data of a pattern to be measured are tracked in an inspection region 20 having a predetermined size extracted from a master pattern and the pattern to be measured. Edge data of the pattern to be measured are sequentially labeled as n1 to n18. However, edge data n8 and n17 are not registered in a master pattern Ma formed from two facing straight lines representing pattern edges and a master pattern Mb similarly formed from two facing straight lines. In this manner, the short circuit of the pattern to be measured can be detected (see, e.g., Japanese Patent Laid-Open No. 6-273132; to be referred to as reference 1 hereinafter).
FIG. 8 explains a conventional inspecting method of detecting an omission or projection. A perpendicular to a central line L is drawn, and the length between the intersection points of the perpendicular and straight lines A1 and A2 representing master pattern edges is obtained in advance as a master pattern width W0. In actual inspection, a perpendicular is drawn from edge data n of a pattern to be measured to the central line L of the master pattern, and the distance between facing edge data is obtained. This distance is a width W of the pattern to be measured. The width W is compared with the master pattern width W0, detecting an omission or projection of the pattern to be measured (see, e.g., Japanese Patent Laid-Open No. 7-110863; to be referred to as reference 2 hereinafter).
The above pattern inspecting apparatus displays only an inspection result at the end of inspection. The operator cannot confirm the content of a defect during inspection.
The conventional pattern inspecting apparatus detects an inspection work defect from the error amount between a master pattern and a pattern to be measured (inspection work). Even if this error is negligible in practical use, the pattern is detected defective. Such excessive detection decreases the product yield.